Pneumatic safety and arming mechanism for fuzes



Sept. 5, 1967 J. A. BORCHERS PNEUMATIC SAFETY AND ARMING MECHANISM FORFUZES 27- I '4 J 2e- 24-%3 33 Filed April 18, 1966 INVENTOR.

JULIUS A. BORCHERS 1 wwflw W Va. yaw

ATTORNEYS.

3,339,488 PNEUMATIC SAFETY AND ARMING MECHANISM FOR FUZES Julius A.Borchers, Richmond, Ind., assignor to Avco Corporation, Richmond, Ind.,a corporation of Delaware Filed Apr. 18, 1966, Ser. No. 543,404 6Claims. (Cl. 10278) ABSTRACT OF THE DISCLOSURE This is a missile fuze ofthe type in which a setback slide mechanism and an arming delaymechanism of the pneumatic type and a detonator carrier are successivelyactuated. A housing is formed with two bores in spaced parallelismhaving a transverse passageway therebetween. A setback slide .andassociated components are mounted in the first of these bores and thesetback slide moves rearwardly to actuate a first lever mounted in thetransverse' passage. When actuated the lever releases a spring urgeddelay arming slide member which is mounted for linear displacement inthe second bore. The duration of the movement of the delay arming slideis controlled by a pneumatic regulator also mounted in the second bore.The delay arming slide in turn actuates a swingably mounted detonatorcarrier to arm said carrier. The arrangement is compact in that thesetback slide and the delay arming slide mechanisms are in spacedparallelism. The detonator carrier is mounted in a chamber which is incommunication with the second bore.

The present invention relates to fuzes, and specifically to safety andarming mechanisms for same in which a pneumatic regulating element isemployed for purposes of accomplishing a time delay in arming.

It is a primary object of the invention to provide, in a fuze, thecombination of three mechanisms: (1) a setback slide, which responds tosetback forces developed during acceleration of a missile to enable oractivate a time delay slide; (2) a time delay slide comprising anelement which is linearly displaced, the displacement being delayed intime while it achieves a magnitude appropriate to permit the time delayslide to activate or enable a detonator carrier mechanism; and (3) adetonator carrier mechanism which is normally restrained to be held inan unarmed position but, when enabled or activated, swings about an axisto assume an armed position at which it places a detonator in alignmentwith the remainder of a firing train.

Another primary object of the invention is to provide a safety andarming fuze mechanism having wide latitudei.e., one in which springstrengths and weights can be varied as desired in order to determine thethreshold of deceleration forces which will cause arming.

Another object of the invention is to provide a fuze which has suchdesign latitude that the requisite delay time can be varied by any oneor more of a number of parameters such as spring strengths, regulatormaterial, regulator geometry, weight of setback element, type of gas orliquid utilized in the regulator, and the characteristics of theregulator.

Another object of the invention is to provide a fuze in which the threeabove-mentioned mechanism are so interlocked that the fuze will be heldsafe against arming until the missile in which it is installed is inflighti.e., in its intended environment and operation.

For a better understanding of the invention, together with other andfurther objects, advantages, and capabilities thereof, reference is madeto the following description of the appended drawings, in which:

FIG. 1 is a sectional view of a preferred form of fuze United StatesPatent in accordance with the invention, being taken with draftsmansliberty in such manner that in the right two-thirds of the figure theobserver looks toward the front of the detonator carrier 30, but in theleft side of the figure the observer looks generally into the time delayslide mechanism;

FIG. 2 is a view of the preferred form of the invention, as taken alongsection line 22 of FIG. 3;

FIG. 3 is a top plan view of the preferred form of the invention; and

FIG. 4 is a fragmentary sectional view as taken along line 4-4 of FIG.1.

Referring now to the drawings, the principal working elements arecontained in a generally cylindrical housing 10 which is adapted to bescrewed onto the base of a fuze, say a proximity fuze of the typeutilized in the nose of a missile or grenade. The housing is suitablymachined and formed to provide suitable mountings and enclosures for theoperating parts now described.

The housing may be manufactured from metal or plastic materials asrequired in order to comply with strength, weight, and environmentalconditions to which it may be subjected. Materials presently consideredare molded plastics, machined steel, and zinc or aluminum die castmgs.

The housing is provided with a pair of bores 11 and 12 extending from aplane near its midsection toward its closed end. A setback releasemechanism is mounted in bore 11. It comprises a pair of locking balls 14and 15, a wedge '16, a wedge setback spring 17, a setback slide 18, anda setback slide spring 19, all collectively referred to as the setbackrelease mechanism. The function of this mechanism is to respond tosetback forces to change the position of a lever 20, hereinafterdescribed. The setback slide spring 19 is a compression springpositioned adjacent the lower portion of the bore 11 to exert a forwardthrust against the setback slide 18, which is accordingly formed with anannular shoulder against which the setback spring abuts. The setbackslide 18 is mounted for linear displacement within the bore 11 and issuitably formed with the annular shoulder aforementioned, with a hollowforwardly extending cylindrical portion for concentrically slidablyaccepting the wedge setback spring 17, wedge 16 and with ports forreceiving the locking balls 14 and 15. It will be apparent from what hasbeen already said that the purpose of the setback slide 18, with itspointed nose projecting rearwardly from the bore 11, is to actuate thelever 20 when a sustained load having the desired number of G forces isapplied.

The wedge setback spring 17 is positioned between a seat formed insetback slide 18 and the Wedge, exerting a forward thrust against thewedge, thereby to exert pressure tending to push the locking balls 14and 15 laterally outwardly and accordingly pushing them in to anenlarged portion of the bore 11 and locking the setback slide againstlinear displacement. The wedge 16 senses the application of G forces,which cause it to seek to decelerate on setback relative to the grenadein which it is installed. The setback release mechanism is associatedwith the lever 20, pivotally mounted at 21 and biased into a normalposition of engagement with the arming time delay slide 22. When thesetback slide release mechanism responds to setback forces ofpredetermined magnitude, it noses 20 into angular displacement andreleases lower lever 20from the pneumatic arming time delay slide 22.Spring 33 normally holds the lever 20 against the pointed nose of thesetback slide 18 and locks the arming time delay slide 22 againstdisplacement.

Within the bore 12 of the housing 10 is mounted the pneumatic armingtime delay system, which comprises a compression spring 23, a slidemember 22, and a time delay regulator presently to be described. Theslide spring 23 is a compression spring which exerts a forward thrust onthe slide 22 and accelerates it forwardly when lever 20 is released fromit. The arming time delay slide 22 is generally bullet-like in shape,having a blunt nose, a tapered cam surface between the nose and its mainbody portion, and further having a bottom body portion suitably formedto perform the functions of being engaged by lever 20 and providing arecess against which spring 23 thrusts.

The function of the arming time delay slide, during its forwarddisplacement, is to release a lever 25 from a detonator carriermechanism presently described, thereby to arm the fuze. The timerequired for the necessary displacement of slide 22 is determinedprimarily by the regulator, which comprises an inverted sac 26 securedbetween suitable washers 27 and 28, washer 28 being formed with anorifice 29. The sac is filled with a suitable gas or fluid which escapesthrough orifice 29 as the sac is compressed or distorted by reason ofthe forward thrust exerted against it by the nose of the arming timedelay slide 22. This sac is also referred to as a diaphragm, and thewasher 28, with orifice 29, is referred to as a restricter.

The time displacement of the arming time delay slide is a function ofthe viscosity of the fluid with which it is filled. It is also afunction of the size, shape, and porosity of the powdered material usedfor the orifice 29. The diaphragm washer 27 acts as a bearing surfacefor the lower side of the flanged portion with which the diaphragm isformed.

The third principal mechanism is the detonator carrier mechanism. Thedetonator carrier 30 is mounted in cavity 35 of the housing and islocked in the safe position by the upper lever 25. When the lever isreleased, the detonator carrier 30 is moved to the armed position by adetonator carrier spring 31, which not only moves the detonator carrierinto that position but also holds it there. The retainer 32 is aU-shaped part used to hold the detonator in place in cavity 35.

The cycle of operation of the novel fuze is as follows: (1) when themissile (such as a mortar shell) is fired, the fuze and the body areaccelerated; (2) the setback force which is developed moves the wedge 16rearwardly against the force of spring 17; (3) the locking balls are nolonger forced laterally outwardly, and they move inwardly, releasing thesetback slide 18; (4) the setback slide is displaced rearwardly againstthe force of spring 19 and disengages lower lever 20 from the armingtime delay slide 22, freeing the latter; (5) the slide spring 23 forcesthe arming time delay slide 24 forwardly; (6) as the arming time delayslide moves forwardly, it is delayed by the regulator; (7) a tapered camsurface on the arming time delay slide impacts upper lever 25 and movesit into position to release detonator carrier 30; (8) the detonatorcarrier, being loaded by spring 31, moves into the armed position.

The setback slide spring 19 provides a safety feature, in that, if thewedge is caused to release locking balls 14 and 15 by dropping orvibration, the wedge setback spring 17 will immediately reposition them,the spring 19 meanwhile preventing displacement of the setback slide.The setback slide will not be freed unless a sustained force isencountered, since the setback spring 17 will force the wedge forward toreposition the locking balls. This design, therefore, permits the fuzeto remain in an arm-safe condition unless the preselected sustainedsetback force for arming is applied.

It will be understood from the foregoing that the detonator is in thearmed position when the detonator carrier swings clockwise approximately90 degrees from the position illustrated in FIG. 1, at which time thedetonator is in line with an electrical contact 34 there shown. Sufiiceit to say that the electrical parts of a proximity fuze are disposed inthe large well in front of that contact, and high explosive material inthe well located below the detonator carrier mechanism illustrated inFIG. 1.

While there has been shown and described what is at present consideredto be the preferred embodiment of the invention, it will be understoodby those of skill in the art that various changes and modifications maybe made therein without departing from the scope of the invention asdefined by the appended claims.

I claim:

1. In a missile fuze, the combination of a setback slide mechanism, anarming delay slide mechanism, a movable detonator carrier mechanismhaving unarmed and armed conditions, and a housing formed to mount saidmechanisms,

in which the setback slide mechanism comprises:

a longitudinally extending setback slide mounted for lineardisplacement,

releasable locking means for normally locking the setback slide againstdisplacement but responsive to acceleration forces to unlock said slide,said slide then being displaced by acceleration forces,

and a first lever normally engaging and restraining the arming delayslide mechanism but being cammed out of engagement therewith by thesetback slide as the setback slide is displaced;

in which the arming time delay mechanism is in spaced parallelism and ina row with the setback slide mechanism and comprises:

a longitudinally extending delay slide member engaged by said firstlever, a first spring means tending to displace the delay slide,

regulating means for delaying the displacement of the delay slidemember, and a second lever normally engaging and restraining thedetonator carrier mechanism but being cammed out of engagement with thedetonator carrier mechanism by the delay slide as the delay slide isdisplaced;

and in which the detonator carrier mechanism comprises:

a detonator carrier normally disposed in unarmed position,

and a second spring means for urging the detonator carrier into armedposition when the second lever is disengaged from the detonator carrier.

2. The combination in accordance with claim 1 in which the setback slideis mounted to be displaced rearwardly by setback forces, and in whichthe arming delay slide is adapted to be displaced forwardly by the firstspring means.

3. The combination in accordance with claim 2, and a third spring meanspositioned yieldably to oppose displacement of the setback slide.

4. The combination in accordance with claim 3 in which the releasablelocking means comprises a wedge element slidably mounted within thesetback slide, a pair of locking balls normally wedged by the wedgeelement to lock the setback slide, and a fourth spring means fornormally urging the wedge element into locking position.

5. The combination in accordance with claim 4 in which the regulatingmeans comprises a fluid-filled sac adapted to be compressed by thearming delay slide, and an orifice through which the fluid flows as thesac is compressed.

6. In a missile fuze of the type in which a setback slide mechanism andan arming delay mechanism and a detonator carrier are successivelyactuated, the combination of:

a housing formed with first and second longitudinally extending parallelbores, arranged in a row and having interior walls, and a chambercommunicating with the second bore and a transversely extendingpassageway between and behind said bores;

a setback slide mechanism comprising a longitudinally extendingpiston-like setback slide member formed with a rearwardly extending noseand mounted for linear displacement within the first of said bores,

a first spring disposed between said housing and said setback slidemember for preventing rearward displacement of the slide except inresponse to sustained setback forces, and

releasable locking means, comprising locking balls and a wedge memberand a second and wedgebiasing spring mounted within the setback slidemember, for locking the setback slide member against displacement, thelocking means being responsive to acceleration forces of setback tounlock the setback slide member, whereupon the setback slide member isdisplaced rearwardly by the continued acceleration forces of setback;

a first lever pivotally mounted in said passageway;

means for normallybiasing said first lever to engage and restrain thearming delay slide member until said first lever is cammed out ofengagement with the arming delay slide mechanism by the nose of thesetback slide member as the setback slide member is displacedrearwardly;

an arming delay mechanism comprising a longitudinally extending delayslide member mounted in the second of said bores and normally engaged bysaid first lever,

a third spring disposed between said delay slide member and said housingfor urging the delay slide member forwardly, and

pneumatic regulating means comprising a sac mounted in said second boreand formed with a rearwardly extending bulge adapted to be depressed asthe delay slide member moves forward, thereby to delay the displacementof said delay slide member and to establish a predetermined timedifferential between setback and arm- 5 g;

and a detonator carrier mechanism comprising a detonator carriernormally disposed in unarmed position in said chamber,

a second pivotally mounted lever, and

BENJAMIN A. BORCHELT, Primary Examiner.

G. H. GLANZMAN, Assistant Examiner. 30

1. IN A MISSILE FUZE, THE COMBINATION OF A SETBACK SLIDE MECHANISM, ANARMING DELAY SLIDE MECHANISM, A MOVABLE DETONATOR CARRIER MECHANISMHAVING UNARMED AND ARMED CONDITIONS, AND A HOUSING FORMED TO MOUNT SAIDMECHANISMS, IN WHICH THE SETBACK SLIDE MECHANISM COMPRISES: ALONGITUDINALLY EXTENDING SETBACK SLIDE MOUNTED FOR LINEAR DISPLACEMENT,RELEASABLE LOCKING MEANS FOR NORMALLY LOCKING THE SETBACK SLIDE AGAINSTDISPLACEMENT BUT RESPONSIVE TO ACCELERATION FORCES TO UNLOCK SAID SLIDE,SAID SLIDE THEN BEING DISPLACED BY ACCELERATION FORCES, AND A FIRSTLEVER NORMALLY ENGAGING AND RESTRAINING THE ARMING DELAY SLIDE MECHANISMBUT BEING CAMMED OUT OF ENGAGEMENT THEREWITH BY THE SETBACK SLIDE AS THESETBACK SLIDE IS DISPLACED; IN WHICH THE ARMING TIME DELAY MECHANISM ISIN SPACED PARALLELISM AND IN A ROW WITH THE SETBACK SLIDE MECHANISM ANDCOMPRISES: A LONGITUDINALLY EXTENDING DELAY SLIDE MEMBER ENGAGED BY SAIDFIEST LEVER, A FIRST SPRING MEANS TENDING TO DISPLACE THE DELAY SLIDE,REGULATING MEANS FOR DELAYING THE DISPLACEMENT OF THE DELAY SLIDEMEMBER, AND A SECOND LEVER NORMALLY ENGAGING AND RESTRAINING THEDETONATOR CARRIER MECHANISM BUT BEING CAMMED OUT OF ENGAGEMENT WITH THEDETONATOR CARRIER MECHANISM BY THE DELAY SLIDE AS THE DELAY SLIDE ISDISPLACED; AND IN WHICH THE DETONATOR CARRIER MECHANISM COMPRISES: ADETONATOR CARRIER NORMALLY DISPOSED IN UNARMED POSITION, AND A SECONDSPRING MEANS FOR URGING THE DETONATOR CARRIER INTO ARMED POSITION WHENTHE SECOND LEVER IS DISENGAGED FROM THE DETONATOR CARRIER.